Phonograph trip mechanism



Jan. 5, 1943. E. o. THOMPSON PHONOGRAPH 'IRII MECHANISM Filed Sept. 5, 1941 rotated by a motor (not shown).

Patented Jan. 5, 1943 PHONOGRAPH TRIP MECHANISM Elmer 0. Thompson, Grasmere, N. Y., assignor to Philco Radio and Television Corporation, Philadelphia, Pa., a corporation of Delaware Application September a, 1941, Serial No. 409,425

17 Claims.

This invention relates to automatic phonographs of the type having a trip mechanism for initiating the operation of auxiliary apparatus,-

such as a relay, at the end of the playing of a record. More particularly, the invention relates to a phonograph wherein the auxiliary apparatus is initiated by a trip mechanism responsive to the rate of movement of the tone arm pickup over the record being reproduced.

A trip mechanism of the abovetype is adapted to function at the end of a recording as the pickup stylus moves out of the reproducing grooves into a spiral of greater pitch, or an eccentric groove; or in the event that the tone arm moves too rapidly at any time during the playing of a recording. By way of example, the trip itself may be of the type which is triggered by the more rapid than normal movement of the pickup and which, in turn, serves to trigger a suitable mechanism-adaptedto lift the tone arm and swing it off the record, in order that a succeeding recording may be placed upon the turntable.

The principal object of the present" invention is to provide a simplified and improved trip mech- 'anismemploying a novel principle of operation.

' moves at a greater than normal rate.

The present invention may be fully understood by reference to the accompanying drawing and following description.

In the drawing:

Fig. 1 is a top plan view of a phonograph em-' bodying one form of this invention; and

Fig. 2 is a sectional view of the device of Fig. 1. a

' The present invention is illustrated as it may be applied to a simple automatic phonograph, A turntable I having a smooth undersurface is mounted on a baseplate 2 and is adapted to be On the turntable there is indicated a recording 3 having a clear outer peripheral margin 4, a low pitch spiral sound groove 5 and a high pitch spiral terminating groove 6. Pivotally mounted on the baseplate 2 there is a hollow vertical shaft 1 as shown. At its upper endjshaft I supports the outer end of a tone arm 8 from a. pivot 8a.

Areproducingelement 8 is carried by the inner end of the tone arm. At its lower end the shaft 1. carries a pivotally mounted arm I 0 which isfree to rotate on shaft I. Near its pivotal mounting arm l0 has an upstanding projection it which is adapted to be engaged by a yoke I member 12 which is fixedly secured to theshaft 1.. immediately above the arm i0. As shown, yoke I! hasan opening i3 into which projection it extends., Yoke l2' and projection ll form a lost motion driving linkage between the tone arm 8 and the arm II. the purpose of which will be made clear hereinafter.

The baseplate 2 has a large opening ll positioned beneath 'the'turntable, and arm i0 is formed near its free end with an upwardly extending portion I! which extends through the baseplate opening. On the free end of arm l0 there is pivotally supported an element l6 and at the free end of element It there is pivotally supported a second elementl'l. Both elements It and il have openings in the center thereof in which there are mounted small wheels it which are preferably covered with soft rubber or a like substance. As shown in the drawing, these wheels I8 arenormally maintained in engagement with the undersurface of the turntable,.

preferably by inherent resilience in the arm i0.

If desired, however, the wheels l8 could be caused to move over any suitable rotating surface other than the turntable as, for example, a cylindrical drum rotating about a horizontal axis. Both elements It. and i! are provided with projecting fingers II which extend toward stops 20 mounted on arm}! and element It respectively. Light wire springs II are provided to normally maintain the projections i8 againstthestops 20 by tending to rotate elements i8 and I! about their respective pivotal mountings. .carries an extending finger 22 which terminates in a contact element 23, and element ll carries a The contacts 23 and 24 are arranged to be in closely spaced relation when the elements It and I! are in the relative position shown in the drawing. These contacts may constitute the switch contacts for a relay (not shown) which is adapted when energized to initiate the actuation of arecord change mechanism. Such a relay and mechanism are illustrated in the copending application 01R. 5.

Crammer and C. A. Pittman, Serial No. 407,788,

filed August 21, 1941.

which extends above and below the baseplate '55 In order to lie: the arm ill to lower the wheels The element 16 I8 away from the undersurface of turntable I, there is provided a linkage actuable by the tone arm 8. This linkage comprises the angle member which has a portion extending u wardly through the hollow shaft 1 to en age the undersurface of the tone arm rearwardly of the pivot 8a and a second portion parallel to the first portion extending downwardly into fixed engagement with the arm ill (see Fig. 2).

Having thus described the several components of one form of this device, the operation thereof may now be considered. The tone arm 8 is movable about the pivot formed by the shaft 1 from a position clear of the turntable I, laterally over the record to the inner terminating groove thereof. The tone arm is also movable about its pivot 8a from a position where the reproducing element 9 engages the recording to an elevated position where element 8 is free of the recording.

These movements of the tone arm may be automatically controlled in case the present invention is applied to some form of automatic'record changing mechanism. In Fig. 1 the reproducing element is shown on a recording near the center thereof. In this condition the tone arm is being advanced toward the center of the record at a relatively slow rate. Yoke I2 is rotating with tone arm 8 and by virtue of the engagement of yoke l2 with projection H whichhas just taken place, the arm [0. is also being rotated. The turntable l, running at a steady speed, causes the two wheels I? to rotate about their l8 and I1 will assume their normal positions.

' Thereafter the tone arm 8 may be rotated lataxes of rotation, and the lements l6 and II in,- I

itially to assume the positions shown in Fig. 1.

As the tone arm 8 moves toward the center of the record. the arm l0 leads the elements l8 and I1 radially inward across he undersurface of the turntable. As the end arm ID moves very slowly through an are about shaft I as a center, the pivotal connection between arm Ill and element l6 draws the wheel l8 of element [8 slowly inward, the element [6 rotating very gradually counter-clockwise about the point of contact of the wheel with the undersurface of the turntable This movement of element l6 causes element I! to rotate very gradually in a clockwise direction about the point of contact of its wheel with the turntable surface. It should be remembered that the springs 2| are very light, and they permit the above-mentioned movements of elements l6 and I1. These movements tend to bring contacts 23 and 24 toward each other, but since the said movements are very gradual and since arm l0 moves through a small arc, the contacts are not brought into engagement with one another until the reproducer 9 reaches the end of the recording.

When the reproducer 9 enters the spiral terminating groove 8 the arms 8 and III are caused to rotate more rapidly and element I5 is caused to rotate more rapidly counter-clockwise about the point of contact of its wheel [8 and turntable l. Similarly the rapid rotational movement of element [6 causes element i! to rotate more rapidly clockwise about the point of contact of its wheel IS with the turntable The rapid opposed movements of elements 16 and I1 cause the contacts 23, 24 to engage one another to initiate operation of a device such as above mentioned.

Assuming that the trip mechanism serves to actuate an automatic record changer, the latter will elevate tone arm 8. This motion will cause link 25 to be moved downwardly so as to flex arm Hi and cause the disengagement of wheels 18 from the turntable l, whereupon the elements erally clear of the recording. During the first portion of this movement, arm Ill will remain stationary while the yoke i2 is rotated until proiection H is engaged by the opposite face of the opening l3. Opening l3 preferably is so designed that when tone arm 8 has been moved outward to its extreme lateral position, the arm ID will have been moved to a position just inside the outer margin of turntable I. Then when a new recording has been placed on turntable l, the tone arm 8 will be swung laterally inward and placed on the outer edge of the record. During this movement the arm I0 will again remain stationary due to the lost motion connection between yoke l2 and projection H, and as the tone arm is lowered onto the edge of the record the'arm ID will flex upward to cause wheels II to again engage turntable I, the elements It and I1 having assumed the relative positions shown in the drawing under the influence of the springs 2|.

Thereafter the tone arm 8 will move across the record toward the inner edge thereof while arm in will remain stationary until projection ii. is engaged by yoke l2. From this point, the cycle above described will be repeated. From the foregoing description it will be seen that the tripping action is effected when the joint between elements l6 and I1 is broken" sufllcienhy to cause engagement of contacts 28 and 24 which constitute a trip means. The parts are so constructed that the joint does not break" sufficiently to operate the trip means 23, 24 until the reproducer 9 enters the groove 6.

In cases where the arm i0 is of reasonable length compared to the radius of turntable I or where the angular rotation of the arm I0 during a cycle is very small, it will be possible to eliminate the element I! by attaching the contacts 23, 24 to the arm I!) and element l6 respectively, but on the opposite sides thereof so that the contacts will become engaged upon more rapid than normal movement of the tone arm. However, it is preferable to use both elements l6 and I! to insure that the changes in relative angular relation of arm l0 and member l6 as the latter moves slowly in toward the center of the tumtable will not efiect closure of contacts 23, 24. Also the arm In need not be pivotally mounted on shaft I. Instead, it may be mounted on guides so that the end of the arm carrying element IE will move radially of the turntable under the control of a flexible cable or other linkage driven by rotation of the shaft 1.

From the above description it will be seen that the present invention provides a novel electrical trip mechanism for automatic phonographs. It will be understood however that the principle disclosed herein is not limited to the single embodiment shown but that other forms, such as above mentioned, may be constructed in accordance with the invention as defined in the appended claims.

I claim:

1. In a trip mechanism for an automatic phonograph having a tone arm including a stylus adapted to move over a recording, a moving surface, a first means engaging said surface, a second means adapted to lead said first means over said moving surface in accordance with the movement of the tone arm over the recording, said first and second means being movable relr ie to each other in accordance with the rate of movement of nograph having 2,307,179 r said tonearm, and trip means operable-by the relative movement of said first and second means upon movement of said tonearm at a greater thannormalrate. l

2. In a trip mechanism for an automatic phonograph having a turntable and atone arm adapted to move over ac-ecording on the turn table, a first means engaging a surface of said turntable, a second means fiexibly connected to said first means for guiding said first means across said surface in accordancewiththe movement-of the tone am over the recording, saidfiexible connection of said first and second means being such that relative movement of said first and second means will be caused upon-movement of-said tone arm at a greater thannormal rate, and trip movements means operable by said relative 3. In a trip mechanism for an automatic pho nograph having a tone arm adapted tomove over a recording, a moving surface. a first means mak-' ing rolling contact with said surface, a second means flexibly connected to said first means for guiding said first means across saidsurfa'ce'in a direction difi'erent from the "direction of rotation of said surface in accordance with the movement of the tone arm over the recording, saidflexibleconnection of said first and secondmeans being about an axis normal to the'plane oi' movement of said moving surface at the point of contact of said surf-ace and said first means such that relative rotation of said first and second means will be caused upon movement of, said tone arm at a greater than normal rate, and trip means operable by the relative rotation of said first and second means. I

4. In a trip mechanism im an automatic phonograph having a tone arm adapted to move over a recording, a moving surface, a first means mak plane of movement of said movingsurface at the] point of contact of said surface and said first means, whereby relative rotation'of said first and second means. will be caused upon movement greater than normal rate,-

of said tone arm at a I and trip means operable by the relative rotation of said first and second means. I v

5. In a trip mechanism for an automatic phoover a recording, a moving surface; a first means making rolling contact with said surface, afseoond means pivotally connected to'said first means; for guiding said first'means laterally across said surface in accordance with the movement ofthe tone arm over the record, a first member associated with said first means, and a'second member associated with said second means, said pivot connection of said first and second means being such as to permitrelativerotation of, said'first and second means when said tone arm is advanced I at a greater than normal rate, said relative rotation of said means being such as to cause action of said first and second members to initiate operation of the trip mechanism. g

6. In a trip mechanism for an automatic phonograph having a tone arm including a stylus adapted to move over a recording, a moving surface, a first means engaging said surface, a second means flexibly connected to said first means ior guiding said first means across said surface a tone arm {adapted to move ative rotation oi said in accordance with the movement of the tone [8 turntable, a second vanced at agreater than normal rate, said rela-- tive movement of saidmeans-being suchas to causecoaction of said first andsecond members to initiate operation of-the trip-mechanism.

: "I. In a trip mechanism for an automatic phonograph having an adapted to move over a recording onthe turntable, a first'means engaging a surfaceof said means flexibly connected'to said first means-for guiding said'first means laterally across said surface in accordance with the movement oi theitone arm over the-record,lan

electrical contact onsaid first means, andam electrical contact on saidsecond means," said contacts I being normally adjacent each other but spaced apart, said flexible connection of" said first andisecond meansbeing such as to permit relative movement of said first and second means whensaid tone 'arm is advanced at a greater than normal 8, In a trip mechanism for anautomaticphonograph having a tone arm adapted to'move over a recording, a moving surfacega firstmean's engagingsaidsurface, a second'means flexibly connected to said first means for guiding said first meansacross'said surface in" accordance with the movement or the tone arm over the recording; said second'means comprising a firstmember engaging said surface and a guide member controllable by said tone am, said first member and said guidemember' being fieniblyconnected, said flexible connections being suchthat relative movementof said first and second means will be caused upon movement of said tone arm-at a greater than normal rate, and trip means operable by the relative movement of said first and s'econdfmeans.

- rpm a trip mechanism me an" automatic pimnograph having a tone'arm adapted to move over a recording, amoving surface, a first'niea'ns making rollingcontact with said surface, a second means pivotally connected to said first means for guiding said first means across said surface in accordance with the movement of thetone arm overtherecording, said first means being carried by and "maintained in engagement. with said moving surface by said'second means, said Divot conne'ctionfof said first and second means being normal tothe plane of movementoi' said moving surface at the point of contact ot'said surface and said first means, whereby relative rotation of said first and second means will be caused upon movement; of said tone arm at a greater than normal rate,and trip I first-and second means.

' 10. In atrip mechanism for an automatic phonograph having a tone arm including a stylus adapted to move over a recording, a moving surface, a first means engaging said surface, a first member associated with said first means, a second means adapted to lead said first means over said [moving surface in accordance with the movement of the tone arm over the recording, and a second member associated with said second means, said first and second means being movable relative to each other in accordance with the rate of movement of said tone arm, said relative movement of said means being such as turntable and a:- tone arm rat to cause engagement of said -'conmeans operable by the relnograph having a tone arm adapted to move over he time arm from 4- 2,307,110 I to cause coaction of said first and second memrange of movement of said secondmeans is less bars to initiate operation of the trip mechanism. 'than the range of movement of the tone arm, 11. In a trip mechanism for an automatic phoand means operable upon the disengagement of the recording for disengaging a recording, a moving surface, a first means en- 5 said first means from said surface, said pivot congaging said surface; a second means adapted to nection of said first and second means being norlead said first means over said moving surface in mal to the plane of movement of said moving suraccordance with the movement of the tone arm face at the point of contact of said surface and over the recording, means coupling said tone arm said first means, whereby relative rotation of to said second me connection such that the range of movement of movement of said tone arm at a greater than said second means is less than the range of ov normal rate, to initiate operation of the trip ment of the tone arm, said first and second means mechanism.

being movable relative to each other in accord- 15. In a trip mechanism for an automatic ance with the rate of movement of said tone arm, is P S -Dh h v a tone m adapted to m v and trip means oper said first and second means upon movement of said tone arm at a greater than normal rate.

making rolling contact with said surface, a sec-- ond means pivotally connected to said first means 12. In a trip mechanism for an automatic phofor guiding said first means across said surface nograph having a tone arm adapted to move over an in accordance with the movement of the tone arm a recording, a moving surface, a first means enover the recording, means operable upon the disgaging said surface, a second means adapted to engagement of the tone arm from the recording lead said first means over said moving surface a for disengaging said first means from said surin accordance with the movement of the tone face, and light spring and stop means tending to arm over the recording, said first and second maintain a normalangular relation between said means being movable relative to each other in first and second means when said last means is accordance with the rate of movement of said operable, said pivot connection of said first and tone arm, said relative movement of said first and second means being normal to the plane of moveation of 'the ment of said moving surface at the point of consecond means serving to eflect oper trip mechanism upon movement of said tone arm 3" tact of said surface and said first means, whereby at a greater than normal rate, and means operrelative rotation of said first and second means able upon the disengagement 'of the tone "arm will be caused, upon movement of said tone arm from the recording for disengaging said first at a greater than normal rate, to initiate operameans from said surface. tion of the trip mechanism. a I

13. In a trip mechanism for an automatic pho- 35 16. In a trip mechanism for an automatic nograph having a tone arm adapted to move over phonograph having a tone arm adapted to move a recording, a moving surface, a first means enover a recording, a, moving surface, a member gaging said surface, a second means flexibly conmovable by said tone arm in proximity to said nected to said first means for guiding said first surface, a second member attached to said first means across said surface in accordance with 40 member and movable relatively thereto, means the movement of the tone am over the recordtending to maintain a predetermined positional ing, said second means comprising a first memrelationship between said members, a roller on ber engaging said surface and a guide member said second member engaging said surface and controllable by said tone am, said first member adapted to effect gradual movement of said secand said guide member being flexibly connected, in 0nd member relative to said first member as the means coupling said tone arm to said second roller moves over said surface, and trip means means including a lost motion connection such operable by the relative movement of said memthat the range of movement of said second means bers upon movement of said tone arm at a is less than the range of movement of the tone greater than normal rate. arm. and means operable upon the disengageso 1'7. In a trip mechanism for an automatic ment of the tone arm from the recording for disphonograph having a tone arm adapted to move engaging said first, means and said first member over a recording, a moving surface, a member from said surface, Sai fle ("inflection-1 being movable by said tone arm, a second member pivsuch vthat relative rotation of said first and secotally connected to said first member, means and means will be caused upon movement of said tending to maintain a predetermined positional tone arm at a greater than normal rate, said relationship between said members, a roller on relative rotation of said means serving to effect H said second member engaging said surface and operation of the trip mechanism. adapted to effect gradual movement of said sec- 14. In a trip mechanism an automatic and member relative to said first member as the phonograph having a tonearm adapted to mov m roller moves over said surface, a third member over a recording. 8 moving Surface, fl means pivotally connected to said second member, means making rolling c n w Said tending to maintain a predetermined positional and mean pivotally connected to said first means relationship between said second and third memfor guiding said first means across said surface bers, a roller on said third member engaging said in accordance with the movement of the tone arm surface, whereby said third member is gradually over the recordi d fi means b91118 carmoved relative to said second member, and trip ried by and maintained in eng e W Said means operable by the relative movement of said moving su ce y id nd m an means second and third members upon movement'oi coupling said tone arm to said second means insaid tone arm at a greater than normal rate. eluding a lost motion connection such that the mm THOMPSON,

ans and including a lost motion 10 said first and second means will be caused, upon able by relative movement of over 'a recording, a moving surface, a first means i 

